The invention relates to an apparatus .Iadd. and method .Iaddend.for analyzing material.
In particular, the invention relates to an apparatus for determining stiffness and energy loss characteristics of a given material as a function of temperature or as a function of time at a given temperature.
It is conventional to analyze material in the above manner by way of a thermomechanical analyzer. The determination of the properties of the material is usually achieved by distorting a sample of the material and measuring the effect of the material on the energy injected into it with any of a number of available techniques.
While it is known that it is best to generate shear stresses in a sample in order to determine the properties thereof during thermomechanical analysis, it is not possible with known methods and apparatus to subject the sample which is analyzed to stresses in pure shear. The stressing of the sample with the known methods and apparatus are always accompanied by undesirable tensile or compressive forces which detract from the accuracy of the analysis and which increase the energy required to achieve the desired analysis. Thus, with known methods and apparatus it is unavoidable that the sample will be stressed in excess of an optimum amount.
A further drawback of the present state of the art resides in the fact that the analysis cannot always be carried out with the desired accuracy. Furthermore it is not possible with the known techniques to isolate the stresses to which the sample is subjected from the stresses in the structure which carries the sample.